From a74f9d57d972444f66f96497fbf9ce9ed91a86a2 Mon Sep 17 00:00:00 2001
From: Moritz Bunkus <m.bunkus@linet-services.de>
Date: Tue, 30 Jun 2020 13:52:59 +0200
Subject: [PATCH] =?utf8?q?DBUpgrade-Mechanismus:=20umgekehrte=20Abh=C3=A4n?=
 =?utf8?q?gigkeiten=20mit=20=C2=BBrequired=5Fby=C2=AB=20angeben=20k=C3=B6n?=
 =?utf8?q?nen?=
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Existierender Mechanismus mit »depends« sagt: die Scripte in »depends«
müssen ausgeführt werden, bevor ich selber ausgeführt werde.

Mit »required_by« kann man das Umgekehrte angeben: ich selber muss
ausgeführt werden, bevor die Scripte in »required_by« ausgeführt
werden können.

Damit kann man z.B. kundenspezifische SQL-Upgrades schreiben, die
erzwungen vor offiziellen SQL-Upgrades ausgeführt werden, ohne die
offiziellen Upgrade-Dateien dafür verändern zu müssen.
---
 SL/DBUpgrade2.pm | 22 ++++++++++++++++------
 1 file changed, 16 insertions(+), 6 deletions(-)

diff --git a/SL/DBUpgrade2.pm b/SL/DBUpgrade2.pm
index 3918ad40d..0b14eca5b 100644
--- a/SL/DBUpgrade2.pm
+++ b/SL/DBUpgrade2.pm
@@ -56,9 +56,10 @@ sub parse_dbupdate_controls {
     $file =~ s|.*/||;
 
     my $control = {
-      "priority" => 1000,
-      "depends"  => [],
-      "locales"  => [],
+      priority    => 1000,
+      depends     => [],
+      required_by => [],
+      locales     => [],
     };
 
     while (<IN>) {
@@ -71,8 +72,8 @@ sub parse_dbupdate_controls {
       my @fields = split(/\s*:\s*/, $_, 2);
       next unless (scalar(@fields) == 2);
 
-      if ($fields[0] eq "depends") {
-        push(@{$control->{"depends"}}, split(/\s+/, $fields[1]));
+      if ($fields[0] =~ m{^(?:depends|required_by)$}) {
+        push(@{$control->{$fields[0]}}, split(/\s+/, $fields[1]));
       } elsif ($fields[0] eq "locales") {
         push @{$control->{locales}}, $fields[1];
       } else {
@@ -100,7 +101,7 @@ sub parse_dbupdate_controls {
 
     delete @{$control}{qw(depth applied)};
 
-    my @unknown_keys = grep { !m{^ (?: depends | description | file | ignore | locales | may_fail | priority | superuser_privileges | tag ) $}x } keys %{ $control };
+    my @unknown_keys = grep { !m{^ (?: depends | required_by | description | file | ignore | locales | may_fail | priority | superuser_privileges | tag ) $}x } keys %{ $control };
     if (@unknown_keys) {
       _control_error($form, $file_name, sprintf($locale->text("Unknown control fields: #1", join(' ', sort({ lc $a cmp lc $b } @unknown_keys)))));
     }
@@ -114,6 +115,15 @@ sub parse_dbupdate_controls {
     close(IN);
   }
 
+  foreach my $name (keys %all_controls) {
+    my $control = $all_controls{$name};
+
+    foreach my $dependency (@{ delete $control->{required_by} }) {
+      _control_error($form, $control->{"file"}, sprintf($locale->text("Unknown dependency '%s'."), $dependency)) if (!defined($all_controls{$dependency}));
+      push @{ $all_controls{$dependency}->{depends} }, $name;
+    }
+  }
+
   foreach my $control (values(%all_controls)) {
     foreach my $dependency (@{$control->{"depends"}}) {
       _control_error($form, $control->{"file"}, sprintf($locale->text("Unknown dependency '%s'."), $dependency)) if (!defined($all_controls{$dependency}));
-- 
2.20.1